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Evidence that dysregulated DNA mismatch repair characterizes human nonmelanoma skin cancer
Author(s) -
Young L.C.,
Listgarten J.,
Trotter M.J.,
Andrew S.E.,
Tron V.A.
Publication year - 2008
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2007.08249.x
Subject(s) - msh2 , dna mismatch repair , msh6 , carcinogenesis , dna repair , skin cancer , biology , microsatellite instability , basal cell carcinoma , mlh1 , dna damage , cancer research , nucleotide excision repair , pms2 , genetics , cancer , pathology , dna , medicine , basal cell , microsatellite , gene , allele
Summary Background In addition to an established role in the repair of postreplicative DNA errors, DNA mismatch repair (MMR) proteins also contribute to cellular responses to exogenous DNA damage. Previously, we have shown that Msh2 ‐null mice display increased sensitivity to ultraviolet (UV) B‐induced tumorigenesis, but squamous cell carcinomas (SCC) generated are microsatellite stable, suggesting a role for MMR other than postreplicative repair in UV‐induced cutaneous tumour formation. Objectives We questioned whether there was evidence of MMR dysfunction in human SCC, thus validating the mouse models of MMR‐dependent UVB‐induced skin cancer. Methods Using tissue microarrays we examined both nuclear and cytoplasmic levels of MMR proteins MSH2, MSH6, MSH3, MLH1 and PMS2 in more than 200 cases of cutaneous SCC and basal cell carcinoma (BCC). Results We found that subsets of these 10 MMR protein measures were increased in nonmelanoma skin cancer (NMSC) compared with normal epidermal samples; this was particularly true of SCC. In fact, based on post hoc tests and MMR protein distribution patterns, BCC was distinct from SCC. With the exception of nuclear MSH2, the BCC had lower levels of identified MMR protein measures than SCC. We believe this to be important because not only is SCC more aggressive than BCC, but evidence suggests that these two NMSC subtypes arise through different molecular pathways. Conclusions In combination with previously established roles for MMR proteins in response to UVB‐induced DNA damage, our data point towards an expanded perspective of the importance of MMR proteins in the suppression of UVB‐induced tumorigenesis and, potentially, tumour behaviour.